The present invention relates to a surface discharge type plasma display panel (PLASMA DISPLAY PANEL) having a matrix display system, and more particularly to a structure of a black stripe formed in parallel with a scanning electrode pair in each region between pixels in order to enhance a contrast of a screen.
FIG. 10 is an exploded perspective view showing a sectional structure of a unit pixel of an AC surface discharge type plasma display panel (hereinafter referred to as a PDP) according to the prior art described in U.S. Pat. No. 5,661,500, for example.
A PDP shown in FIG. 10 is of a surface discharge type having a three-electrode structure, and comprises a first glass substrate 1 provided on a screen side, a scanning electrode pair (X, Y) formed adjacently in parallel with each other in a transverse direction (a direction of A shown in FIG. 10) on a surface of the glass substrate 1, a dielectric layer 4 for AC driving which has a discharging protective film 5 formed on a surface thereof, a second glass substrate 6 opposed to the first glass substrate 1, a plurality of barrier ribs 7 formed in a direction orthogonal to the scanning electrode pair (X, Y) and defining a spacing dimension of a discharge space 10 by abutting on the discharging protective film 5, phosphors 9R, 9G and 9B having three primary colors of R (red), G (green) and B (blue) provided between the barrier ribs 7, address electrodes (W) provided in the second glass substrate 6 each corresponding to each of the phosphors 9R, 9G and 9B, and the like.
EU denotes unit luminescent areas each corresponding to each of the phosphors 9R, 9G and 9B. A unit pixel region EG is formed by three unit luminescent areas EU.
A discharge region is partitioned by the barrier ribs 7 for each unit luminescent area EU. The discharge space 10 thus partitioned is filled with a neon-xenon mixed gas at a pressure of about 500 Torr as a discharge gas for radiating ultraviolet rays for exciting the phosphors 9R, 9G and 9B.
Since the scanning electrode pair (X, Y) is to be provided on the screen side, it comprises band-shaped transparent conductor films (for example, a nesa film:tin oxide) 3 and metal films (for example, Ag:silver) 2 for compensating for conductive properties of the films 3.
An upper layer portion of the barrier rib 7, that is, a top 8 of the barrier rib is formed by a layer mixed with a black pigment in order to obtain the effect of enhancing contrast performance of a screen.
In such a surface discharge type PDP, a surface discharge occurs in each of intersecting portions of the scanning electrode pairs (X, Y) and the address electrodes (W) so that the unit luminescent areas EU are defined.
Accordingly, a portion corresponding to each unit luminescent area EU can be caused to selectively emit light. Thus, full color display can be obtained by the combination of R, G and B.
FIG. 11 is a plan view schematically showing a unit pixel portion of the PDP illustrated in FIG. 10.
As shown in FIG. 11, the PDP has a structure in which each unit pixel region EG constituting the screen is formed by the three unit luminescent areas EU arranged in one direction and the phosphors 9R, 9G and 9B having three colors for full color display are arranged in order corresponding to the unit luminescent areas EU.
In such a unit pixel region EG, the scanning electrode pair (X, Y) formed in the array direction of the unit luminescent area EU is arranged as electrodes for causing a surface discharge.
FIG. 12 is a plan view schematically showing another example according to the prior art in which black stripes 20 are provided between the unit pixel regions EG in parallel with the scanning electrode pairs (X, Y) in order to enhance the contrast of the screen in the conventional surface discharge type PDP described above, and FIG. 13 is an exploded perspective view showing a sectional structure of FIG. 12.
FIG. 14 is an exploded perspective view showing the first glass substrate 1 provided on the screen side in FIG. 13, which is seen from a non-screen side.
In FIGS. 13 and 14, regions enclosed by a heavy broken line indicate the black stripes 20.
FIG. 15 is a sectional view showing a state in which the first glass substrate 1 having the dielectric layer 4 and the discharging protective film 5 formed on the scanning electrode pairs (X, Y) and the black stripes 20 and the second glass substrate 6 having the barrier ribs 7 formed thereon are stuck together, which is seen just horizontally (in the A direction of FIG. 10).
In the drawings, for example, a thickness of the scanning electrode X or Y formed by the metal film 2 and the transparent conductor film 3 (that is, the sum of thicknesses of the metal film 2 and the transparent conductor film 3) is about 0.5 xcexcm, while a thickness of the black stripe 20 is about 10 xcexcm. The dielectric layer 4 having a thickness of about 30 xcexcm and the discharging protective film 5 having a thickness of about 0.7 xcexcm are formed with almost uniform thicknesses over the scanning electrodes X and Y and the black stripes 20.
For this reason, surface irregularities (concavities and convexities) are generated on the surfaces of the dielectric layer 4 and the discharging protective film 5 due to the thicknesses of the scanning electrodes X and Y and the black stripes 20 which are provided on the surface of the glass substrate 1. In particular, convex portions are enlarged over the black stripes 20.
By the way, the convex portions of the protective discharging film 5 provided above the black stripes 20 on the first substrate 1 side intersect with and abut on the tops 8 of the barrier ribs 7 provided on the second substrate 6 side. Consequently, the discharge spaces 10 are defined.
In such a conventional AC surface discharge type PDP, however, when the first substrate 1 side and the second substrate 6 side are stuck together to form the discharge spaces 10, the protective discharging film 5 provided on the first substrate 1 side abuts on the tops 8 of the barrier ribs provided on the second substrate 6 side in the convex portions generated due to the thickness of the black stripe 20 as shown in FIG. 15. Therefore, unnecessary clearances 30 are generated between the top 8 of the barrier rib and the protective discharging film 5.
The clearance 30 has a thickness of about 3 xcexcm in a central portion between the adjacent black stripes 20 so that an extra discharge space exists in a boundary portion between the adjacent unit luminescent areas EU.
Accordingly, also in a case where surface discharge should be caused in a specific unit luminescent area, for example, a unit luminescent area EU (R) and should not be caused in unit luminescent areas EU (G) and EU (B) adjacent to both sides of the unit luminescent area EU (R), there is a problem in that the surface discharge gets over the top 8 of the barrier rib 7 through the clearance 30 which is the extra discharge space, thereby causing erroneous discharge in the unit luminescent areas EU (G) and EU (B) on both sides or affecting the surface discharge in the unit luminescent areas EU (G) and EU (B) on both sides (for example, voltage margins are reduced in the unit luminescent areas EU (G) and EU (B) on both sides), and the like.
The present invention has been made in order to eliminate the above-described drawbacks of the prior art, and has an object to provide a high performance surface discharge type PDP capable of reducing extra discharge spaces (that is, the clearances 30) generated between adjacent unit luminescent areas due to a thickness of a black stripe and of lessening defective writing caused by an erroneous discharge or the like.
The present invention provides a surface discharge plasma display comprising a first glass substrate having a plurality of scanning electrode pairs parallel with each other and black stripes parallel with the plurality of scanning electrode pairs formed on one main surface thereof and having a dielectric layer covering them, and a second glass substrate including a plurality of address electrodes formed in parallel with each other in a direction orthogonal to the plurality of scanning electrode pairs and having a plurality of barrier ribs parallel with the plurality of address electrodes, the plurality of barrier ribs abutting on the dielectric layer to form discharge spaces each corresponding to each of the plurality of address electrodes, wherein each of the black stripes formed on the first glass substrate has portions each intersecting with a top of corresponding one of the plurality of barrier ribs on the second glass substrate, the portions being cut into pieces. Therefore, a clearance can be reduced in a portion where the top of the barrier rib abuts on a surface of the dielectric layer, thereby narrowing an unnecessary discharge space between adjacent unit luminescent areas EU in a direction orthogonal to the barrier ribs which cause erroneous discharge. In addition, a convex portion of a surface of a discharging protective film formed on the dielectric layer, which is generated due to the black stripe, also functions as a barrier rib for separating discharge between the adjacent unit luminescent areas EU in a parallel direction with the barrier ribs, thereby preventing defective writing from being caused by the erroneous discharge or the like between the adjacent unit luminescent areas EU.
In the surface discharge plasma display according to the present invention, furthermore, the black stripes formed on the first glass substrate are constituted by a plurality of layers, at least one of the plurality of layers having portions each intersecting with the top of the corresponding one of the plurality of barrier ribs on the second glass substrate which are cut into pieces. Therefore, it is possible to prevent defective writing from being caused by the erroneous discharge or the like between the adjacent unit luminescent areas EU in horizontal and vertical directions with respect to the barrier ribs. In addition, since one of the layers of the black stripe is not cut into pieces, reliable light shielding effects can be obtained.
Moreover, the present invention provides a surface discharge plasma display comprising a first glass substrate having a plurality of scanning electrode pairs parallel with each other and black stripes parallel with the plurality of scanning electrode pairs formed on one main surface thereof and having a dielectric layer covering them, and a second glass substrate including a plurality of address electrodes formed in parallel with each other in a direction orthogonal to the plurality of scanning electrode pairs and having a plurality of barrier ribs parallel with the plurality of address electrodes, the plurality of barrier ribs abutting on the dielectric layer to form discharge spaces each corresponding to each of the plurality of address electrodes, wherein a top of each one of the plurality of barrier ribs provided on the second glass substrate includes notch portions formed in portions intersecting with the black stripes so that convex portions of the dielectric layer generated due to the black stripes formed on the first glass substrate are fitted in the notch portions. Therefore, a surface of the dielectric layer can come in contact with the tops of the barrier ribs in comparatively flat portions where the black stripe is not formed. A clearance can further be reduced in the portion where the top of the barrier rib abuts on the dielectric layer, thereby narrowing an unnecessary discharge space between adjacent unit luminescent areas EU in a direction orthogonal to the barrier ribs which cause erroneous discharge. In addition, a convex portion of a surface of a discharging protective film formed on the dielectric layer, which is generated due to the black stripe, also functions as a barrier rib for separating the discharge between the adjacent unit luminescent areas EU in a parallel direction with the barrier ribs, thereby preventing defective writing from being caused by the erroneous discharge or the like between the adjacent unit luminescent areas EU.
In the surface discharge plasma display according to the present invention, furthermore, a discharging protective film is formed on a surface of the dielectric layer. Therefore, an unnecessary discharge space can be reduced between adjacent unit luminescent areas EU, thereby lessening defective writing caused by the erroneous discharge or the like. In addition, it is also possible to obtain the effect of relaxing ion bombardment during the discharge of the dielectric layer.
In the surface discharge plasma display according to the present invention, moreover, the top of the barrier rib is formed by a layer mixed with a black pigment. Therefore, an unnecessary discharge space can be reduced between adjacent unit luminescent areas EU, thereby lessening defective writing caused by the erroneous discharge or the like. In addition, a contrast of a screen can also be enhanced.